>I every one.
>I'm always learning through you guys Q&A.. ^^;
>
>I have a question about DBC security.
>I must lock the DBC structure ( table structure and relation and so on.... )
>only it must be access in program code(in my application), any foxpro environment or any tools can't access the DBC.

If you're in a network environment, you can store DBCs and related files in a separate read-only directory, I find that to be a good solution. Users with vfp can look, but they can't touch. Of course, this only works if you're not doing any on-the-fly DBC modifications...